下列说法正确的是:() A.使用机械可以省力当然也能省功 B.做功的过程就是能量 发布时间:2017-06-04 12:01 │ 来源:www.tikuol.com 题型:选择题 问题: 下列说法正确的是:( )A.使用机械可以省力当然也能省功B.做功的过程就是能量转化的过程C.能量在转化和转移过程中总量保持不变,所以无需节约能源D.热机将内能转化为机械能的效率可以达到100%
题型:选择题 按要求改写句子。1. Please write down your name here. (改为否定句) Please ____ write down your name here. 2. I swept the floor just now. (改为一般疑问句) ____ you ____ the floor just now? 3. She needs to wear her school uniform. (改为否定句) She ____ ____ to wear her school uniform.4. I often help my mum do the laundry on Sundays. (改为同义句) I often help my mum ____ ____ on Sundays. 5. The boy is cleaning the table. (对画线部分提问) ____ ____ the boy ____ ? 查看答案